Actuator mounted to torque box

ABSTRACT

An actuator system mounted to a gas turbine engine that communicates mechanical power for positioning variable guide vanes within the gas turbine engine. The actuator system includes a torque box having components for communicating mechanical power to the variable guide vanes for positioning the vanes and an actuator mechanically coupled to provide mechanical power to the components of the torque box used to communicate the provided mechanical power to the inlet guide vanes. The actuator is mounted to the torque box via an elongate fastener extending in one direction and another elongate fastener extending in another direction.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation of U.S. patent application Ser. No.13/485,325, filed on May 31, 2012, and entitled “ACTUATOR MOUNTED TOTORQUE BOX,” the disclosure of which is incorporated by reference in itsentirety.

BACKGROUND

The present invention is related to gas turbine engines, and inparticular to actuators for positioning inlet guide vanes and/orrotatable guide vanes.

Gas turbine engines rely on rotating and stationary components toeffectively and efficiently control the flow of air through the engine.Rotating components include rotor blades employed in compressor andturbine sections for compressing air and extracting energy from airafter combustion. Stationary components include vanes placed in theairflow to aid in directing airflow. By varying the position of thevanes (i.e., rotating them to vary the profile provided to the airflow),airflow characteristics can be optimized for various operatingconditions.

The mechanism for providing precise, controlled, and uniform actuationof the vanes is a linear actuator connected to the plurality of vaneslocated circumferentially around the engine via a series of linkages.The actuator is typically mounted to the exterior of the engine case,and communicates power to the series of linkages via a bell crank orsimilar mechanical device mounted on a torque box. Installation andalignment of the actuator relative to the bell crank is critical toachieving a desired positioning of the vanes. However, factors such asthermal growth during various flight conditions can adversely affect thealignment of the actuator with the bell crank, which results in errorsin between the desired position of inlet guide vanes and the actualposition of the inlet guide vanes.

SUMMARY

An actuation system mounted to a gas turbine engine that communicatesmechanical power for positioning inlet guide vanes within the gasturbine engine. The actuation system includes a torque box havingcomponents for communicating mechanical power to position the inletguide vanes and an actuator mechanically coupled to provide mechanicalpower to the components of the torque box. The actuator is mounted tothe torque box via an elongate fastener extending in one direction andanother elongate fastener extending in another direction.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a gas turbine engine according to anembodiment of the present invention.

FIG. 2 is a top-view of an actuator and torque box positioned above anengine case according to an embodiment of the present invention.

FIG. 3 is a side view illustrating the attachment of the actuator to thetorque box according to an embodiment of the present invention.

FIG. 4 is an isometric view illustrating the attachment of an actuatorto the torque box according to another embodiment of the presentinvention.

DETAILED DESCRIPTION

FIG. 1 is a cross-sectional view of a compressor section of gas turbineengine 10 according to an embodiment of the present invention, althoughthe principles of the present invention may be applied to a turbinesection of gas turbine engine 10 as well. In the cross-sectional viewshown in FIG. 1, gas turbine engine 10 includes a plurality ofstationary variable guide vanes (VGV) 12 and a plurality of rotatingblades 14. With respect to stationary VGVs 12, each is rotatable aboutan axis 16 that is substantially perpendicular with engine centerlineaxis 18. The performance of gas turbine engine 10 is modified, in part,by adjusting the position of stationary VGVs 12 to selectively varyairflow characteristics of the engine.

Mechanical force used to change the position of VGVs 12 is provided byactuator 20, and communicated via torque box 22 and a plurality of arms24 to stationary VGVs 12. Actuator 20 and torque box 22 are positionedradially outward of engine case 26. As discussed in more detail below,torque box 22 is mechanically attached to engine case 26, while actuator20 is mechanically coupled to torque box 22. A benefit of connectingactuator 20 to torque box 22, rather than directly to engine case 26 isimproved alignment between actuator 20 and torque box 22. In particular,when both the torque box and actuator are attached to the engine case,tolerances associated with attachment of both the torque box andactuator to the engine case, coupled with thermal growth issues cannegatively impact the alignment between the two, which results inpositioning errors in the stationary VGVs.

FIG. 2 is a top-view of actuator 20 and torque box 22 positioned aboveengine case 26 according to an embodiment of the present invention.Actuator 20 is a linear actuator that provides mechanical force in thedirection indicated by line 32. Actuator arm 30 is connected to dog-bonearm 34, which in turn is connected to bell crank 36. In the embodimentshown in FIG. 2, bell crank 36 includes first end 38, second end 40, andthird end 42. First end 38 is mechanically coupled to dog-bone arm 34.Second end 40 is connected to a first stage synchronizing ring (notshown). Third end 42 is mechanically coupled to arm 24. Bell crank 36 issupported by and pivotally connected to torque box 22 at pivot point 44.Mechanical force applied by actuator 20 in the direction indicated byline 32 results in bell crank 36 pivoting about point 44, resulting inmechanical force being applied by third end 42 to arms 24 in a directionindicated by arrow 45, in a direction opposite to the direction of firstend 38. Conversely, mechanical force applied by actuator 20 in adirection opposite of line 32 results in mechanical force being appliedby third end 42 to arms 24 in a direction opposite that indicated byarrow 45.

A plurality of synchronizing rings (not shown) are positionedcircumferentially around engine case 26, including at least onesynchronizing ring located forward of bell crank 36 attached to actuator20 via second end 40 of bell crank 36. Each synchronizing ring isassociated with the VGVs 12 a, 12 b, and 12 c, respectively, shown inFIG. 1. Mechanical motion provided via arms 24 in a direction indicatedby arrow 45 is communicated to the synchronizing rings, which results inthe synchronizing rings moving in a circumferential direction thatresults in positioning of VGVs 12 a, 12 b, and 12 c.

Actuator 20 is mechanically fixed to torque box 22. In the embodimentshown in FIG. 2, three bolts 52 a, 52 b, and 52 c attach actuator 20 totorque box 22. Bolts 52 a and 52 b extend radially into torque box 22,while bolt 52 c extends tangentially (i.e., at an angle perpendicular tobolts 52 a and 52 b) into torque box 22. Bolt 52 b is located forward ofbolt 52 a, and may be located at a radial height different than that ofbolt 52 a.

FIG. 3 is a cross-sectional view taken along line 3-3 shown in FIG. 2,illustrating the attachment of actuator 20 to torque box 22 according toan embodiment of the present invention. In the embodiment shown in FIG.3, actuator 20 is located adjacent torque box 22. Bolt 52 c is visible,and illustrates attachment of actuator 20 to torque box 22. In addition,the cross-sectional view shown in FIG. 3 illustrates the placement ofhelical coil insert 54 c within torque box 22 to secure bolt 52 c.

In addition, the embodiment shown in FIG. 3 illustrate the placement ofactuator 20 adjacent to torque box 22, while maintaining the placementof actuator 20 proximate to engine case 26 (as opposed to locatingactuator 20 radially outward of torque box 22). This decreases thecross-sectional profile of actuator 20 and torque box 22, and isbeneficial in decreasing the overall size of the engine.

FIG. 4 is an isometric view illustrating the attachment of actuator 20to torque box 22 according to another embodiment of the presentinvention. In the embodiment shown in FIG. 4, actuator 60 ismechanically coupled to torque box 62 by three bolts 72 a, 72 b, and 72c. However, in the embodiment shown in FIG. 4, bolts 72 a and 72 b aredirected tangentially through actuator 60 to torque box 62, while onlybolt 72 c is directed radially through actuator 60 to torque box 62. Inaddition, helical coil inserts 74 a, 74 b and 74 c and washers 76 a, 76b, and 76 c are shown. Helical coil inserts 74 a-74 c are provided inthe bolt holes to lock bolts 72 a-72 c in place once installed (i.e.,prevent loosening rotation of the bolts). Washers 76 a-76 c are locatedadjacent to actuator 60 to prevent damage to the surface of actuator 60.

Bolts 72 a and 72 b secure actuator 60 to torque box 62 in a directiontangential to a circumference associated with the engine centerline axis18. Bolt 72 c secures actuator 60 to torque box 62 in a radialdirection. Bolts 72 a and 72 b are generally aligned with one another,but perpendicular to bolt 72 c. The combination of bolts 72 a, 72 b and72 c secure actuator 20 to torque box 22.

In addition, bolt 72 c is located on a plane radially inward of torquebox 62 with bolts 72 a and 72 b tangential to the torque box 22. Thelocation of bolt 72 c relative to bolts 72 a and 72 b prevents axialbending or flexing of actuator 60 relative to torque box 62, therebyimproving alignment between actuator 60 and torque box 62. In addition,locating sleeve 78 a is employed in conjunction with bolt 72 a, to alignactuator 60 with torque box 62.

While the invention has been described with reference to an exemplaryembodiment(s), it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted forelements thereof without departing from the scope of the invention. Inaddition, many modifications may be made to adapt a particular situationor material to the teachings of the invention without departing from theessential scope thereof. Therefore, it is intended that the inventionnot be limited to the particular embodiment(s) disclosed, but that theinvention will include all embodiments falling within the scope of theappended claims.

1. An actuator system comprising: a torque box having components forcommunicating mechanical power to variable guide vanes for positioning;and an actuator mechanically coupled to provide mechanical power to thecomponents of the torque box used to communicate the provided mechanicalpower to the variable guide vanes, wherein the actuator is mounteddirectly to the torque box via a first elongate fastener extending in afirst direction between a first hole in the actuator and a second holein the torque box and a second elongate fastener extending in a seconddirection that is different from the first direction between a thirdhole in the actuator and a fourth hole in the torque box.
 2. Theactuator system of claim 1, wherein the first direction is perpendicularto the second direction.
 3. The actuator system of claim 2, wherein thefirst direction extends radially from a centerline axis of the gasturbine engine and the second direction is tangential to the centerlineaxis.
 4. The actuator system of claim 1, wherein the torque box ismounted to an exterior side of an engine case associated with the gasturbine engine.
 5. The actuator system of claim 1, wherein the actuatoris further mounted directly to the torque box via a third elongatefastener extending in one of the first direction and the seconddirection.
 6. The actuator system of claim 5, wherein the third elongatefastener is attached to the torque box at a location radially inward ofthe first and/or second elongate fasteners.
 7. The actuator system ofclaim 5, wherein the first direction is perpendicular to the seconddirection.
 8. The actuator system of claim 6, wherein the firstdirection extends radially from a centerline axis of the gas turbineengine and the second direction is tangential to the centerline axis. 9.The actuator system of claim 1, wherein the actuator is a linearactuator that communicates mechanical power in a direction parallel withan engine centerline axis.
 10. The actuator system of claim 9, whereinthe torque box includes a bell crank having at least a first end and asecond end, wherein the bell crank is pivotally attached to the torquebox at a pivot point located between the first end and the second end.11. The actuator system of claim 10, wherein the first end of the bellcrank is attached to the linear actuator, and the second end of the bellcrank is attached to linkages for communicating mechanical power to thevariable guide vanes.
 12. A gas turbine engine comprising: an enginecase; a compressor and/or turbine stage having at least a firstplurality of stationary variable guide vanes (VGVs) circumferentiallyspaced around the gas turbine engine radially inward of the engine case,and a second plurality of stationary variable guide vanes (VGVs)circumferentially spaced around the gas turbine engine radially inwardof the engine case, wherein the first plurality of VGVs are axiallyspaced from the second plurality of VGVs; a torque box mounted to theengine case that includes components for communicating mechanical powerto the first plurality of VGVs and the second plurality of VGVs; and alinear actuator mounted directly to the torque box via a first elongatefastener extending in a first direction between a first hole in theactuator and a second hole in the torque box and a second elongatefastener extending in a second direction that is different than thefirst direction between a third hole in the actuator and a fourth holein the torque box and coupled to provide mechanical force to thecomponents of the torque box to selectively position the first pluralityof VGVs and the second plurality of VGVs.
 13. The gas turbine engine ofclaim 12, wherein the first direction is perpendicular to the seconddirection.
 14. The gas turbine engine of claim 13, wherein the firstdirection extends radially from a centerline axis of the gas turbineengine and the second direction is tangential to the centerline axis.15. The gas turbine engine of claim 14, wherein the torque box ismounted to an exterior side of an engine case associated with the gasturbine engine.
 16. The gas turbine engine of claim 12, wherein theactuator is further mounted directly to the torque box via a thirdelongate fastener extending in one of the first direction and the seconddirection.
 17. The gas turbine engine of claim 16, wherein the thirdelongate fastener is attached to the torque box at a location radiallyinward of the first and/or second elongate fasteners.
 18. The gasturbine engine of claim 16, wherein the first direction is perpendicularto the second direction.
 19. The gas turbine engine of claim 12, whereinthe torque box includes a bell crank having at least a first end and asecond end, wherein the bell crank is pivotally attached to the torquebox at a pivot point located between the first end and the second end.20. The gas turbine engine of claim 19, wherein the first end of thebell crank is attached to the linear actuator, and the second end of thebell crank is attached to linkages for communicating mechanical power tothe variable guide vanes.